The present invention relates to an improved transmission mechanism used to control the movement of a presser in sewing machines.
There are a variety of sewing machines on the market, which can be divided into two categories-hand-activated and electro-activated. The former is generally used in ordinary households while the latter is widely used in factories.
The need exists for a durable, inexpensive and easily constructed or repaired transmission mechanism in an electro-activated sewing machine. In the past, sewing machines have been constructed with the transmission mechanism positioned horizontally under the carriage of the sewing machine.
The traditional transmission mechanism for a sewing machine is very complicated, containing a large number of parts that are exposed to the environment and are thereby easily contaminated by dust, etc., which causes malfunctions to occur. Another disadvantage of the traditional transmission mechanism is that the presser moves vertically while the plunger of the transmission means moves horizontally. Therefore, extra parts are required by the transmission means to transform the horizontal movement of the plunger of the transmission means into the vertical movement of the presser. Consequently, the exposure of these members outside the transmission means makes the total length thereof relatively large, which in turn requires the horizontal orientation of the transmission mechanism resulting in an increase in the cost and the difficulty of repair.
The art has long sought a transmission mechanism which is durable, inexpensive and easily constructed or repaired. As shown below the transmission mechanism of the present invention meets this need.